On Sat, 29 Jan 2011, Kang Min wrote:

Thanks Prof Ripley, the condition worked!
Btw I tried to search ?repl but I don't have documentation for it. Is
it in a non-basic package?

I meant grepl: the edit messed up (but not on my screen, as sometimes happens when working remotely). The point is that 'perl=TRUE' guarantees that [A-J] is interpreted in ASCII order.



On Jan 29, 6:54 pm, Prof Brian Ripley <rip...@stats.ox.ac.uk> wrote:
The grep comdition is "[A-J]"

BTW, why there are lots of unnecessary steps here, including using
cbind() and subset():

x <- rep(LETTERS[1:20],3)
y <- rep(1:3, 20)
z <- paste(x,y, sep="")
random.data <- rnorm(60)
data <- data.frame(z, random.data)
data[grepl("[A-J]", z), ]

Now (for the paranoid and not needed in this example) in general the
effect of "[A-Z]" depends on the locale, so you could write out
"[ABCDEFIJK]" or create it by

cond <- paste("[", paste(LETTERS[1:10], collapse=""), "]", sep="")

Or use repl("[A-J]", z, perl=TRUE).



On Sat, 29 Jan 2011, Kang Min wrote:
Hi all,

I would like to subset a dataframe by using part of the level name.

x <- rep(LETTERS[1:20],3)
y <- rep(1:3, 20)
z <- paste(x,y, sep="")
random.data <- rnorm(60)
data <- as.data.frame(cbind(z, random.data))

I need rows that contain the letters A to J, so I tried:

subset(data, grepl(LETTERS[1:10], z)) # got only rows with A
subset(data, z %in% LETTERS[1:10]) # got no rows

I think I'm getting close to the solution but need a little bit of
help here, thanks in advance.

Kang Min

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Brian D. Ripley,                  rip...@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
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______________________________________________
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PLEASE do read the posting guidehttp://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

______________________________________________
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.


--
Brian D. Ripley,                  rip...@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

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